Males born to obese women are more likely to be overweight at birth and develop metabolic complications in later life, including liver disease and diabetes.

The way that male sex hormones activate pathways in the developing liver is partly to blame, according to a new study led by University of South Australia (UniSA) researchers looking at the impact of maternal obesity on foetal liver androgen signalling.

Male foetuses of obese pregnant women have different signals that are activated by male sex hormones in the liver, which encourages them to prioritise growth at the expense of their health.

Androgens give men their male characteristics and are crucial in their development, but if there are too many, male foetuses grow too large, causing not only problems at birth, but impacting liver function as an adult, said UniSA researcher Dr Ashley Meakin.

Female foetuses exposed to excess testosterone from an obese pregnancy are wired to switch off the androgen pathway in the liver, restricting their growth and lowering the risks of metabolic disorders in adulthood.

“We know there are sex differences in metabolic disorders in later life in response to maternal obesity,” said Dr Meakin.

“Men are more prone to non-alcohol fatty liver diseases and diabetes as an adult if their mother is obese during pregnancy and their birth weight is above 4 kg (9 lb 15 oz).”

“They are genetically wired to prioritise androgens because it supports the development of male characteristics including size, but too much androgen is bad.”

There is a fine balance for women getting the right nutrition in pregnancy to ensure optimal conditions for their unborn child to flourish, said study lead author Professor Janna Morrison, Head of the Early Origins of Adult Health Research Group at UniSA.

“There are also risks for offspring being malnourished during pregnancy. If you are too little, too big, born too early, or a male, you are more vulnerable to negative outcomes later in life. You need the Goldilocks pregnancy: you must be the right size, born at the right time.

“As a society, we urgently need to address obesity. If children were taught early on about the importance of healthy eating, it would carry through into adulthood, including during pregnancy, where the right nutrition is so important.”

Supplements that addressed nutritional imbalances in pregnancy could provide the foetus with the best chance of optimal development in the interim, Dr Meakin said.

A video explaining the findings is available at:

Maternal obesity impacts fetal liver androgen signalling in a sex-specific manner is authored by researchers from the University of South Australia, University of Wyoming and the University of Queensland.